Method and apparatus for heating fluids



s. P. VAUGHN 1,800,235

AND APPARATUS FOR HEATING FLUIDS April 14, 1931.

METHOD Filed Dec. 29, 1923 Patented Apr. 14, 1931 UNITED STATES PATENT OFFICE SIDNEY P. VAUGHN, OF ACKERMAN, MISSISSIBPI METHOD AND APPARATUS FOR HEATING FLUIDS (GRANTED UNDER THE ACT OF MARCH 3, 1883, AS AMENDED APRIL 30, 1928; 370 0. G. 757) My invention relates to the heating of fluids generally, and while the characteristics described herein may be advantageously employed for other purposes than generation of steam, such as for heating air, water, or other fluids, my invention applies particularly to that type of apparatus known as the flash type water tube boiler, and the term boiler will be used generically throughout this specification in describing the fluid containing element encircling the combustion chamber as a means for simplifying the description of the invention.

An object of my invention is to provide means in the combustion chamber of a boiler for converting the heat of the combusting fuel into radiant heat and transfer the heat to the fluid containing element or boiler by radiation in a rapid and eflicient manner.

Another object of my invention is to pro- Vide a primary combustion chamber for the initial combustion of the more volatile constituents of the fuel which will cause said fuel to combust very rapidly and to crack or volatilize the less volatile constituents of said fuel andat the same time keep the flame from contact directly with the fluid containing element While in said chamber; and to provide a secondary combustion chamber,

7 preferably surrounding said primary chamber, and whose outer wall is preferably formed wholly or largely by said fluid con taining element, and in which secondary chamber the combustion continues in close contact and proximity with a wall of said element, fresh air being supplied to said sec-' ondary chamber to promote complete combustion therein. From said secondary chamher the combustion products are preferably carried over one end of said element and into one end of a flue preferably surrounding said element, and in which flue the combustion products are carried in direct contact with a surface, and throughout substantially the length of said element, where said combustion products are carried over the adja' cent ends of said element and chambers to a centrally disposed outlet, said flue being provided preferably with multiple vertical baflies to facilitate the equalization of the draft of said outlet between each of said baflles.

Another object of my invention is to provlde an apparatus by which a supply of heated fluid may be economically maintained at substantially a uniform temperature and in the case of a gaseous fluid at substantially a uniform pressure also, notwithstanding instantly varying demands upon such supply.

Another object of my invention is to pro- Vide, as an integral step in my invention, a method of and apparatus by which the temperature of the steam in the main steam line leading from the boiler to the main power unit regulates thermostatically the supply of feed-fluid and maintains a varying fluid level in the boiler according to the desired temperature of the steam to be used by the main power unit and without substantial and disrupting shocks of such fluid upon the high-pressure boiler and fluid feed pump due to my eliminating the sudden changes of pressure of said fluid upon said boiler and pump as follows:

Supplementing, and as a check upon said thermostatic or other control, I further eliminate said. sudden pressure changes by bypassing the fluid supplied by the pump around said thermostatic control and con veying said fluid from said by-pass through a chack-valve and then an air dome before it enters said boiler; and a still further supplement to and check upon said thermostatic control and said check valve is provided by me by conveying the feed from said pump through a second check-valve and thence to said first check-valve, said second check-valve being adapted to discharge into a pipe or channel leading from the discharge side of said thermostatic controlled valve to the intake side of said pump.

Another object of my invention is to provide a vapor generator containing a high pressure and a low pressure boiler within the same unit, and heated by the hot gases after having supplied their main heat to said high pressure boiler; and by which the feed fluid to be evaporated in the high pressure boiler is previously evaporated in the low pressure boiler and condensed to remove all impurities that may injure the high pressure boiler, and means in the low pressure boiler by which the scale formed, and other impurities, therein may be readily removed without disturbing the other parts of the steam generator.

Other advantages of my invention will be apparent from the following detailed description, when takenin connection with the accompanying drawings; in which,

Fig. 1 is a diagrammatic view partly in side elevation. and partly in section, of the complete apparatus; Fig. 2 is a plan sectional view of the generator forming a part of the apparatus; Fig. 3 is a vertical sectional view of a modified form of generator for the apparatus, showing the fuel nozzle and opening in the lower part of the combustion chamber instead of in the top part.

Referring to the drawings more in detail the vapor generator of the apparatus consists of a suitable metallic casing 1 with a suitable heat insulating lining 2, enclosing a boiler 3, in the form of a cylindrical helical coil of tubing, encircling a central primary combustion chamber A and an annular secondary. combustion chamber Bv separated from each other by a wall 4 with small openings therein, and which is supported by a cross member 48 securely fastened to the lower part of the casing. The wall4= is in the form of a mantle or grill enclosing the primary combustion chamber and is made of any suitable material with a high fusing point. Both ends of the primary combustion chamber A are closed with the exception of a small opening 5 in one end through which fuel and air are supplied to the combustion chamber. 011 the left side of the center line of the combustion chamber I show the walls thereof as being in the form of a grill in which the rectangular openings 8 connect the primary combustion chamber A with the secondary combustion chamber B, and slant outward in an upward direction to prevent the escaping gases of combustion making a right angle contact with the boiler. Broken fragments 7 of refractory material are placed in the bottom of the combustion chamber which become incandescent in the process of combustion and assist in promoting the combustion of the incoming fuel.

An annular down draft flue 10 is formed within the casing between the lining thereof and the boiler for the escape of the hot' gases thrown off by the secondary combustion chamber. The secondary combustion chamber is closed at the bottom, but has small openings 46 formed therein for supplving an additional quantity of air to the fuel when required. This closure causes the gases of combustion in the secondary combustion chamber to pass over the top of the boiler 3 thence downward in the down draft flue 10,

in a direction opposite to the incoming liquid to be heated. Vertical angular vanes 9 (formed preferably of uniform angularly crimped sheet, preferably of copper, extending completely around and throughout substantially the length of flue 10) are suitably arranged in the down-draft flue 10 to absorb heat from the gases and transmit it to the boiler by convection and radiation. Suitably arranged in the bottom of the casing I provide a chamber 48a which connects the down-draft flue 10 with a discharge opening 47 in the bottom of the casing.

The mantle or grill wall enclosing the primary combustion chamber absorbs heat from the gases of combustion, becomes incandescent, and radiates the heat of the fuel to the boiler, in the same manner as anordinary gas mantle would if surrounded bya liquid containing element. v

I provide a fuel heating and feed system for light hydro-carbon fuels in which the fuel is supplied under pressure from any suitable source through a fuel line 17 to a coiled vaporizing unit in an opening 5 in one end of the combustion chamber. Connected with said fuel heating unit is a fuel nozzle 18 so placed over the opening 5 that it will direct the heated fuel through substantially the center of opening 5 and into the primary combustion chamber and cause the vaporized fuel to carry with it a suflicient supply of air to complete combustion. As a means for regulating the supply of fuel I provide a needle valve 16, in the fuel line 17, which is actuated through a valve stem 15jby a diaphragm regulator 14 acted upon by the pressure within the boiler. Normally, the valve is held open by a spring pressing downwardly upon the diaphragm, which permits the fuel to pass into the combustion chamber, but When the pre-determined working pressure of the boiler is exceeded the spring gives and the valve closes, thereby cutting off the supply of fuel to the boiler until the boiler pressure returns to the normal working pressure.

To describe more fully, the fuel enters the primary combustion chamber A through the opening 5, the more volatile constituents of said fuelbeing in the form of agaseous mixture. Combustion of the more volatile of said fuel takes place in the primary combustion chamber A, and the less volatile of said fuel is further heated toward volatilization and cracking by said heat within chamber A and by impact with fragments 7 and the bottom wall, and deflection against the sides, of said chamber A; thence the combustion constituents pass through the outwardly and upwardly inclined openings 8 in wall t where the less volatile of said fuel is further heated by the walls of openings 8 and further volatilized and cracked, and passed combusting into the secondary combustion chamber B, and discharged, at an angle to,

and in the direction of, the travel of the products in chamber B, against the corrugated wall of boiler 3, which, with said openings 8 being in a multiple of horizontal and vertical planes in said cylindrical wall at, prednee a progressive intermingling of the discharges from openings 8, thereby promoting progressive turbulence in chzunber B, rapidity of flame propogation, combusition and fuel economy in close proximity to, and progressive contacts with, the wall of boiler 3, mmbustionin chamber B being furthered by the openings 46 inducting air therein .in the direction which the contents of chamber B fi-ow.

Thence, the combustion products pass v 1' the adjacent end of boiler 3 and into the adjfoining end of down-draft flue l0, surrounding' the outer Wall, and in direct contact throughout its length of, boiler 3; thence,

the combusted products are: passed over the opposite end of boiler 3, and the bottoms of chambers A and B, to a centrally disposed draft opening 47; the vertical battles 9 in flue l0 promoting the equal distribution between each of said bafllesof the draft of said open ing 47.

The secondary combustion chamber 13 is of progressively increasing volume, in the direction of its outlet end, attained, in the instance shown in the drawings, by the cot verging wall 4 of the primary combustion chamber A, which, with the restricted area of flue l0, slows up the flow of the products through chamber B and increases relatively the aforesaid turbulence of the combusting products and prolongs their direct contacts with the inner surface of boiler In boilers of all types the accumulation and formation of so called scale on the inside walls of the water containing element causes a great deal of trouble and can be eliminated only by the use of pure water. In my invention I provide a method of and means for obtaining pure distilled water at all times for the boiler proper by incorporating in the walls of the casing l, and displacing lining 2 to the extent thereof, a low pressure evaporating chamber or boiler 37,

i in direct contact with, and capable of absorbing heat from, the exhaust gases passing down the gas flue betweenthe coil of pipe forming the high pressure boiler 3 and the low pressure boiler 37, and cap-able of evaporating just enough water to make up the loss in feed water due to evaporation and leakage. In the outside walls of the low pressure boiler 37 I provide a detachableman-hole plate 39 which may be removed at any time for cleaning the scale from the evaporating unit 37 without disturbing any other part of the plant. WVa-ter is fed to the low pressure boiler 37 by gravity from a main supply tank through a pipe 36 entering the lower part of the boiler 37. The

main supply tank is placed on a level with reference to the low pressure boiler 37 so that all the water in the tank ill enter the low pressure boiler as it is evaporated. Vhen evaporation takes place the vapor exhausts through a pipe 38 leading from the top part of the low pressure boiler 37, through a float controlled valve 49 placed inside of a pure feed water tank ll), thence said vapor passes through pipe 42 leading to the top of a condenser ell above the pure feed water tank. The vapor is then condensed to a degree just below the vaporizing point and passes in the form of pure water from the bottom of condenser 41 through a pipe 43 by gravity into the pure feed water tank 40. The valve 49 in the pure feed water tank connects pipe line 38 with pipe line 42 leading to the condenser and is controlled by a float all that rises and falls with the water level in the pure feed water tank 40. Normally when the water level in the pure feed water tank 40 is at a predetermined level the Heat action keeps the valve 49 closed and prevents vapor entering the condenser. 'When the water level drops the float drops and opens the valve, permitting the vapor to enter the condenser and condense until the normal water level is again obtained. If the valve is closed and the pressure in the boiler 37 rises sufliciently, it forces all the water in the boiler back into the main supply tank 35 and no further evaporation takes place until the valve 49 opens and releases the pressure. It will be seen therefore that the pure feed water evaporating unit is designed to evaporate just enough IIlFllZe up water from tank 35 to replace the pure feed water lost in the operation of the plant.

I attain a further conservation of fuel and apparatus by the following means whereby the exhaust vapor from the main power generating plant is returned to, and enters the top of, the same aforesaid condenser 40, through an independent opening in the top part of the condenser 41, condenses. and then passes into the pure feed water supply tank 40 through said same pipe 43 that also conveys to said tank 40 the condensation from boiler 37.

The apparatus for supplying the liquid to the high pressure boiler 3 is adapted to supply the liquid in varying quantities and in proportion to the variations in the demand for steam. While some of the advantages of my invention may be realized by the use of various types of generators in connection with the apparatus for supplying and controlling the liquid for the high pressure boiler, the best results can be obtained by the use of a boiler in which the liquid is gradually or progressively heated from its point of entrance to tank 35 to the point where it leaves the high pressure boiler as a superheated vapor and in which only a relatively small quantity of the liquid is maintained at the temperature of vaporization corresponding to the pressure at which the boiler is to be operated. These conditions have been best realized by me in an apparatus wherein a boiler consisting of a continuous pipe and described herein as a coiled pipe or boiler 3 encircling a combustion chamber and in which the gases of combustion pass the coil in direction with and then opposite to the flow of fluid within the coil.

Referring to the drawings Fig. l, a feed pump 26 driven by the main engine or other power generating unit receives water from the pure feed water tank 10 through a suction pipe 27 and discharges it through a pipe 28 into the main feed water pipe 11 connected to the boiler 3. The steam used by the main power generating unit is supplied by the boiler 3 through a pipe 12 connecting the boiler with a double sweep T passage formed in a head block 13 which is the upper member of an automatic teed-water regulating device. The passages formed in the head block 13 connect the boiler with a fuel control diaphragm regulator 14, previously described, and also connects the boiler with a pipe 20 containing a thermostat, or the metal of which pipe 20.may constitute said thermostat, through which pipe 20, and connecting pipe 23, passes all the steamused by the main power generating unit. The head block 13 is connected by tie rods 21 and 22 to a lower supporting base 24,111 which a passage is formed connecting the pump discharge pipe 28 with the main feed pipe ll'leading to the boiler. Connecting the head block 13 with the thermostatic tube 20, is a valve 19 adapted to be turnedoif to prevent condensation of steam in the tube20 when steam is not being'used by the main power generating plant. Incorporated-in the supporting base 2% and in the passage connecting the pump discharge pipe 28 with the main feed pipe 11, is a bypass valve 25 connecting said passage with a return pipe 32, 33, connected with the intake of the pump 26. The by-pass valve 25 is opened and closed by its stem'being longitudinally moved by the contraction and exiansion of the thermostatic tube 20, a throttle valve, steam pipe 23 leading to the power generating unit as a means of throttling the steam. A safetyby-pass check valve 29 connects the discharge pipe 28 of the pump 26 with the return pipes 32 and 33 there y bypassing the water discharged from the pump 26 when the pressure in the boiler becomes excessive. A valve 29a may connect withthe mainfeed-water pipe line 11, between the check valve 30 and the boiler 3, with the return pipe line 32 and will act as a safety valve for the boiler when the pressure therein exceeds the working pressure by returning a part of the water content of the boiler through said valve and pipes 32, 33. and 27 to pacity 0t airdome 31 will at all times adequately permit the withdrawal of enough fluid for safety from boiler 3.

A check valve 30 is provided in the main teed pipe line 11 between the'boiler and the by-pass valve 25 to prevent the contents of the boiler escaping through the bypass valve 25 when it is open. An air chamber or dome 31 .is provided in the main feed pipe line 11 also, between the boiler and the check valve 30, to obtain an even and shockless circulation to the boiler when there is a sudden variation in the demand for steam. This air chamber or dome also acts as a storage for the water being pumped into the boiler, and when there is a sudden demandfor steam and the pressure in the boiler drops, such as would happen in starting the main or any additional engine, the air in the chamber or dome forces the water in the air chamber into the boiler and keeps up the circulation in advance of the opening of check-valve 30 to admit water or other fluid that may be required from pump 26, when the pressure in said airdome 31 and boiler 3 falls below the point at which check-valve 30 is set to open toward boiler 3. The air chamber within its capacity, initially withdraws water from the boiler when the pressure suddenly becomes excessive as wouldbe the case it the main or any engine were suddenly stopped after having been run at full speed. I

To explain more fully, we will assume that the main engine is in operation by steam from pipe 23 and that the water pump 26 is con nected with it and also is in operation. We will assume also that the by-pass valve 25, operated by the expansion and contraction of the tube 20, or the thermostat contained therein, leading from the boiler to the main steam line 23, is set to open full when the temperature of the steam being used by the main engine and passing through the tube 20 falls to 400 degrees and set to close fully when the temperature of the steam reaches a temperature of 600 degrees. If the amount or" water being pumped into the boiler is greater than the amount of steam being used the water level will rise, also the pressure will rise. Should the pressure in the boiler exceed the maximum. working pressure the safety bypass valve 29 will open and the water being pumped will return to the intake side of the pump, and also-to tank 40 when part of the contentof boiler 3 is also discharging due to a temporary excess of pressure, through re turn pipes 32, 33 and 27. If the water level in the boiler rises too high in the boiler it will lower the temperature of the steam being used by the power generating unit, which will cause the thermostatic tube. 20 to contract and open the bypass valve 25, and thereby by-pass the water back to the pump 26 through the return pipe 32, 33 and to circulate through said ump 20, as heretofore de scribed. Should the Water level in the boiler start falling the temperature of the steam being used by the main power generating unit will rise in proportion until it reaches the maximum of 600 degrees, at which time the bypass valve 25 will be closed by the expansion of the thermostatic tube 20 and cause more water to enter the boiler. Since the area of the opening in the bypass valve variesin direct ratio to the temperature of the steam being used by the main power generating unit, a time will occur while the steam iseing used at a uniform rate, when the quantity of water entering the boiler will equal exactly the quantity of steam being used.

The steam pressure is normally regulated by varying the supply of fuel according to the pressure inthe boiler through the use of an automatic fuel valve 16 operated by a regulating diaphragm 14 which is acted upon by the pressure in the boiler, but at times the pressure will rise suddenly, such as would be the case were the steam shut off suddenly from the main power generating unit and the engine allowed to idle and operate the feed water pump. In such cases the safety by-pa-ss valve 29 will open and by-pass the water back to the pump intake.

When theboiler is empty and it is desired tov get. up steam, water may be forced into the boiler by a hand pump until a. suflicient quantity has been pumped to operate the main power generating unit to which the main feed water pump is attached.

In accordance with the patent. statutes, I have described what I now believe to be the best embodiment of my invention, but I do not wish. to be understood thereby as limiting myself or the scope of my invention, as manymodifications may be made without departing from the spirit of my invention, and

all such I aim to include in the scope of the appended claims.

The invention herein described; may be manufactured and used by or for the Government of the United States for governmental purposes without the payment to me of any royalty thereon or therefor.

What I claim as new and desire to secure by Letters Patent is: o

1. In the operation of vaporizing a fluid by heat, the method of controlling the supply of fluid to the vaporizing point consisting of the steps of supplying in a definite path from its source the fluid to be vaporized; applying force to the fluid supply at a point in said path; connecting opposite ends of a fluid supply return path with said supply path at points on opposite sides of said force applying point; controlling the volume of said fluid supply to the vaporizing point by regulating the communication between said ath ways by a function of the vaporized uid; further controlling the said supply to the vaporizing point, at a point between said first named control and the vaporizing point, by a function of the fluid in process of being vaporized; and still further controlling the said supply to the vaporizing point at a point between said first control and the point where force is applied to said fluid supply by at said point regulating the volume of the forced fluid supply that may be admitted from said supply path to said return path.

In the method of operation of vaporizing a fluid by heat, the steps of admitting the fuel to a smaller portion of a primary combustion zone of increasing area from said admission onward; igniting and combusting the more volatile constituents of the fuel in said zone; progressively passing the products of combustion from said first named zone at each of a plurality of points and into a smaller portion of a second zone of increasing area from each said admission onward; combusting the lesser volatile constituents of the fuel in said second named zone; transferring said combustion heat to a zone of fluid to be vaporized at a surface of said zone juxtaposed to one of said first two named zones; passing the combusted or combusting products along substantially the remaining surfaces of said fluid zone and thence exhausting said products.

3. In an apparatus for vaporizing a fluid the combination of an apertured wall of refractory material forming the lateral boundaries of a primary combustion chamber; walls of refractory material forming the end walls of said primary combustion chamber; a fuel inlet into said primary combustion chamber through one of said end walls; a wall of thermally conductive material forming with the said apertured wall a secondary combustion chamber, said thermally conductive material forming the external boundaries of a container for said fluid; a wall of thermally insulative material surrounding said wall of thermally conductive material and forming with it a flue space connecting with one end of said secondary combustion chamber; means for supplying fuel to said fuel inlet and means for supplying fluid to said container.

4. In an apparatus for vaporizing a fluid the combination of an apertured wall of refractory material forming the lateral boundaries of a primary combustion chamber of continuously increasing cross-see tional area; walls of refractory material forming the end walls of said primary combustion chamber; a fuel inlet into said primary combustion chamber through one of saidend walls; a wall of thermally con ductive material forming with said apertured thermally conductive material forming the external boundaries ofa container for said fluid; a wall'of' thermally msulative materia1 surrounding said wall of thermally conductive material and forming with it a flue space connecting with one end of said secondary combustion chamber; means for supplying fuel to said fuel inlet and means for supplying fluid to said 'container.

5. In the operation of vaporizing a liquid, the method of fuel and apparatus conservation which consists in vaporizing a fluid under substantially atmospheric pressure in a vaporizing zone substantially juxtaposed to a heating zone; condensing said vapor under substantially atmospheric pressure in a condensing zone; leading said condensed vapor to and revaporizing the same in a separate vaporizing zone juxtaposed to said heating zone and under a pressure greater than atmospheric pressure; and supplying exhaust Vapor to the herein constituted system sub stantially at the entrance to said condensing zone.

6. In the operation. of vaporizing fluids, the methodof fuel and apparatus conservation consisting of combusting fuel in a heating zone; revaporizing under a pressure greater than atmospheric pressure previously condensed vapor in a vaporizing zone substantially juxtaposed to said heating zone and by some of said combustion heat; supplying exhaust vapor to and condensing the same under substantially atmospheric pressure in a condensing zone; returning said condensed vapor to and revaporizing the same in said vaporizing zone; separately vaporizing ina separate vaporizing zone juxtaposed to and by some of the heat of said heating zone and under substantially atmospheric pressure enough make-up fluid to supply operation losses; and conveying the vaporized make-up fluid to and condensing the same in said condensing zone.

7. In the operation of vaporizing a fluid by heat, the method of controlling the supply of fluid to the vaporizing point consisting of the steps of associating a fluid vaporizingarea and a fluid supply area, leading fluid in a supply pathway from the supply to said vaporizing area, connecting opposite ends of a return pathway with said supply pathway at points intermediate said areas, continuously applying force tosaid fluid in said supply pathway at a point between the ends of said return pathway, controlling the supply of fluid to the vaporizing area at a point between saidvaporizing area and the adjacent end of said return pathway by the rela tlve force applied to th'e'fluid and the pres sure of the fluid being vaporized; controlling the supply of fluid to the vaporizing area by regulating by a function of the vaporized isodasa porizing p-olnt; and further controlling the supply of fluid to the vaporizing point by regulating the bypassing oft-he fluid from the supply pathway to the return pathway at a point toward the vaporizing area from the point of application of said force. I

8. In an apparatus for vaporizing fluid by heat, the combination of a vaporizer, piping for supplying fluid to the vaporizer for vaporization therein, a pump connected to said piping, a branch pipe having its opposite ends connected to said piping on opposite sides of said pump, a valve controlling the inlet to said branch pipe at its end nearest the vaporizer, means for controlling said valve by a function of the fluid vaporizedby'the vaporizenmeans between said valve and vaporizer for controlling the supply of fluid to the vaporizer by a function of the fluid being vaporized, and a check valve controlled bypass between said piping and branch pipe at a point intermediate said pump and the first stated valve. 1

9. In an apparatus for vaporizing fluid by heat, the combination of a vaporizer, piping for supplying fluid to the vaporizer for vaporization therein, a pump connected to said piping, a branch pipe having its opposite ends connected to said piping on opposite sides of said pump, a valve controlling the inlet to said branch pipe at its end nearest the vaporizer, means for controlling said valve by a function of the fluid vaporized by the vaporizer, means between said valve and vaporizer for controlling the supply of fluid to the vaporizer by a function of the fluid being vaporized, a check valve controlled bypass between said piping and branch pipe at a'point intermediate said pump and the first stated valve, means for supplying fuel to heat the vaporizer, and means regulated by a function of the vaporizedfluid for controlling the supply of fuel to the vaporizer. j c

10. In an apparatus for vaporizing fluid by heat, the combination of avaporizer, a

supply pipe adapted to lead fluid to the Vacontent of said outlet pipe, and means for V rigidly connecting said supply and outlet pipes adjacent said valve stem.

SIDNEY'P. VAUGHN. 

